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You are here: Home / Gear Reviews / SpotLite Gear Reviews / Platypus GravityWorks Filter Review – 4.0L Water Filtration System

Platypus GravityWorks Filter Review – 4.0L Water Filtration System

by Josh Belcher on December 7, 2016 New Features, SpotLite Gear Reviews

Editor’s Note

What follows is a brief review of a product that has been around for a long time: the Platypus GravityWorks filtration system.

We haven’t conducted a comprehensive long term review of this system to date, even though it’s a popular product with our reader base. Also, the Platypus GravityWorks filter is uniquely positioned as a viable option for group water treatment, and when considered in that context, it’s weight can be justified.

I’ve used the Platypus GravityWorks filtration system on some long treks with Scout groups. The context that made this decision justifiable included:

  • Assignment of water collection and treatment duties to an individual who is responsible for supplying water to the entire crew (thus avoiding the need to have each person use it in turn);
  • Travel in pristine mountain environments where water clarity is high (to avoid the risk of filter clogging as a result of dirty water from snowmelt / glacial melt).

This review provides an alternate perspective from someone who is newer to gravity filtration and is looking at using the Platypus GravityWorks filter for personal use.

– RJ

Introduction

This Platypus GravityWorks filter review will show how this water filtration system provides the backcountry hiker with a reliable and convenient means of filtering water while on the trail. Additionally, this system is available in two versions: The 4.0L (135 oz.) and the 2.0L (68 oz.) models which provide options for filtering water into a clean water reservoir bag or directly into bottles. Also, the gravity fed system offers a quick and effortless approach to filtering large amounts of water while leaving the user hands-free to work on other essential camp chores.

 

Platypus 4.0L Stock Photo

Features

  • 8 liter (135 oz.) total water capacity (perfect for groups or water storage on those longs dry hauls)
  • Dirty zip-lock style bag
    -Easy to fill by dipping the bag into water or using a cup to fill it from smaller sources
    -Hanging strap with buckle
    -Quick disconnect tube attachment
  • In-line gravity water filter
    -Fast hands-free operation
    -Easily backflush the microfilter for maintenance in the field
  • Clean reservoir bag
    -Hanging strap with buckle
    -Screw on hose adaptor for secure seal
    -Hose shut-off clamp for storing and dispensing water at leisure
  • Storage sack
  • Options for using other Platypus products to create a system just right for you

Specifications

  • Weight:
    -Manufacturer states 11.5 oz. (326 g)
    -My scale reads 11.7 oz (331 g)
  • Dimensions: 3.25”W x 9.5”L
  • Filter Media: Hollow Fiber
  • Filter pore size (microns): 0.2
  • Flow Rate: 1.75 liters (59 oz.) per minute
  • Cartridge Life: 1500 liters (50721 oz.)
  • Effective against Protozoa, Bacteria, and Particulates
  • Ineffective against Chemicals/Toxins, Viruses

Field Use

I grew up on hand-pump operated water filter systems and knew no different until a recent rekindling of my adventurous spirit took me back into the wilderness last year. Seeing a gravity filter for the first time? It was a no-brainer… hands-free operation while leaving you available to do other essential camp tasks (not to mention no more sitting on a cold river bank away from the fire for 15 minutes trying to pump into a reservoir bag). Also, having less moving parts to break in my opinion is a winner! In my search for the latest and lightest gear, I found the Platypus GravityWorks system. Available in 4.0L (135 oz.) and 2.0L (68 oz.) versions which allow several options to integrate with other water storage products.

My Rationale for Selection

I selected the 4.0L version for two reasons: 1) Sometimes I hike in groups of 4-5 people, and I felt that this system would provide an excellent resource for supplying a large group. 2) There are areas that I hike where reliable water can be 10+ miles (16+ km) apart. Additionally, if I want to carry extra water, then I can use the up to 8 liters (271 oz.) water capacity to haul it.

Usage Context

That said, I used the system on an 18.3 mile (29.5 km)/2 day hike earlier this year just as it was starting to warm up here in Alabama. I carried the complete kit: dirty bag, clean bag, and all the hoses. Also, I never touched the clean bag or the hose attached to it. I used the dirty bag to scoop water from a nearby stream, hung it on a tree (the hang strap with buckle is a handy addition), and filtered the water straight into my water bladder. In the future, unless I plan to provide water for a group around a campsite, I will only carry the dirty bag with the hose and in-line filter attached which weighs in at 7.3 ounces (207 g).

I’ve gone the way of all the other crazy “gram-counters” out there utilizing electronic scales and spreadsheets to formulate the lowest possible pack weight, even cutting the tags out of my already lightweight tent. Who needs tags anyway? I don’t care about all that useless manufacturer information. WEIGHT! Or the lack thereof and the function of a product is all I care about. Also, I like for stuff to look cool, but that’s not so essential.

Performance

The system worked great when I used it in the field. It did what it was supposed to do, and you can’t ask for more than that. It filtered water quickly and cleanly. The water tasted great, and the whole operation was smooth from start to finish. In my testing, I found the filtering time for 4 liters (135 oz.) of water to be between 4:13 and 4:23. Of course, I have done one thing to adapt mine by cutting a small portion (6” or so)(152 mm) of the tubing to place on the clean side of the filter with the hose shut-off clamp attached. This makes a small portion of the clean tube ready for placement inside your bladder or bottle for filling.

The system is clearly marked to prevent contamination of the clean bag and the connection for each bag is different.  They have a quick disconnect for the dirty side and a screw on attachment for the clean side. Also, the filter is also clearly marked with directional arrows indicating a direction of flow. While the zip-lock style opening of the dirty bag allows for easy water filling and emptying, and it’s large enough to clean and dry for storage. The screw off style cap on the clean bag allows for quick emptying as well.

IMG_8887

IMG_8888

Photos were taken on the Alabama Pinhoti Trail/Section 4 (April 2016).

Performance Highlights

  • Easy filling of the Dirty water bag using the wide zip-lock style opening.
  • No Pumping – Quick gravity filtration straight into your water bladder, bottle, or Clean water reservoir bag.
  • The bag material is sturdy and durable.
  • Straps on both bags include buckles to make hanging around long tree branches straightforward and efficient.
  • The in-line hose shut-off clamp can be used to control the amount of dirty water filtered into the Clean bag. It dispenses drinkable water from the Clean bag when you detach the hose from the filter.
  • Backflush capability enables frequent maintenance to ensure filter performance.  Guidelines suggest a 4-second backflush with every use.

Summary

Strengths

  • Large capacity to accommodate groups or extra water storage along a dry trail.
  • Treatment is effective against Protozoa, Bacteria, and Particulates.
  • The absence of a pump gives the peace-of-mind that with fewer moving parts there is a lower chance of system failure.
  • Lightweight design with the option to reduce weight by leaving the Clean bag behind.
  • The system rolls up into a compact and easily packable bundle and comes with a storage bag.
  • Options for integrating with other Platypus accessories to customize your system.
  • Design allows for easy cleaning and drying for storage of both bags.
  • Clear plastic allows for easy inspection.
  • Cost is competitive with similar type filters systems.

Limitations

  • Other reviews have stated that with extremely dirty water the filter can become clogged with particulates. This may require pre-filtering water through a cloth before using the system.
  • The filter can freeze if not emptied and stored in a warm environment.
  • With shallow water sources, it can be difficult to fill the Dirty bag directly from the source. A cup can be used to remedy this problem.
  • The filter does not treat chemicals/toxins or viruses. A water “purifier” is needed if these are concerns.

Recommendations

I’ve only used the system once in the field, but it worked flawlessly, and I look forward to many more trips with my Platypus. It offers a user-friendly and speedy way to filter water while in the backcountry. I find it superior to pumping by cutting down the time and effort involved and eliminating the moving parts that are subject to break. If viruses are a concern UV or chemical treatment should also be considered. To me, the advantages of this system, as compared to similar systems on the market, are the overall capacity, weight, dirty water filling method, the clear reservoir bags, and the options Platypus offers for integrating accessories.

The 4.0L (135 oz.) version provides a way for me to collect large quantities of water from sources away from the campsite and carry it back for the night. If I fill my 2.5 liters (84.5 oz.) in-pack water bladder at the source then fill the dirty bag to take back to camp, I will have plenty of water in reserve to cook and clean. I will have enough water to refill all my containers before hitting the trail again. The smaller 2.0L (68 oz.) is also available with minimal weight savings and substitutes the clean water bag for a 2-liter soft bottle. Depending upon your specific needs either model should make a great addition to your kit.

Where to Buy the Platypus GravityWorks Filter

Where to Buy Platypus GravityWorks Filter System Bottle Kit - 2 Liter

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Disclosure: some of the links above may be affiliate links, which means if you place an order at one of these retailers, we receive a small commission on this sale. This helps support Backpacking Light, thank you!

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About Josh Belcher

Home › Forums › Platypus GravityWorks Filter Review – 4.0L Water Filtration System

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  • Dec 7, 2016 at 10:33 am #3439246
    Josh Belcher
    Spectator

    @jcbelcher

    Locale: Southeastern, U.S.

    Companion forum thread to: Platypus GravityWorks Filter Review – 4.0L Water Filtration System

    This Platypus Gravity Works filter review focuses on the key strength of the system: high treatment capacity for relative ease.

    Dec 7, 2016 at 11:23 am #3439262
    Philip Tschersich
    BPL Member

    @philip-ak

    Locale: Kodiak Alaska

    “I’ve only used the system once in the field…”

    How can you review a product you have only used once in a real-world scenario? I don’t mean to sound harsh, but it seems like a somewhat premature review. You tested it in April of 2016. Didn’t you have time to use it more after that?

    I have the 2-Liter system, and a friend has the 4-liter. We used his extensively this summer as the main filtering system for groups of up to 5 people, and it worked well for the most part, though the filter became progressively more sluggish in filtering over the course of the season despite regular back-flushes and generally finding relatively clean water sources. I wonder if using a Sawyer-style syringe might clear the filter better than the rather passive back-flush method Platypus suggests. My 2-liter system was defective out of the box with the ‘dirty’ reservoir having it’s welded seam too close to the bag’s edge and the side blew out on the first use.

    It’s easy to populate the “pros” list on a new product, but it’s only possible to enumerate the real “cons” after extensive and heavy use in my opinion.

    Dec 7, 2016 at 11:46 am #3439267
    Bruce Tolley
    BPL Member

    @btolley

    Locale: San Francisco Bay Area

    Josh, Nice review of the 4 liter system.

    I have used both the 4 liter and the 2 liter system. There is a 2 liter option without the second bottle that comes in at 9 plus ounces that comes with a bottle adapter and gives you the option of filling any bottle you want or already own.  I think the main plus of the GravityWorks is that it is VERY fast. If you need water for a group of 2 or more people (esp if they notice the taste of chorine dioxide), it is the way to go. If you are base camping, even more so.

    I have also encountered the clogging issue Phillip mentions when taking water out of Sierra Nevada lakes in the late season. I suspect biofilms growing on the surface were clogging up the hollow fiber filter. No amount of back flushing fixed the problem. But I have had the same issue with pump filters which you can sometimes fix in the field.

    Platypus does warn against dropping or allowing the filter to freeze which applies to Sawyer filters as well.

    Dec 7, 2016 at 12:06 pm #3439269
    Michael Ciofalo
    BPL Member

    @prosf

    Hello Josh,

    Thank you for the comprehensive review!

    I utilized a similar setup last year on a 23 day trek through the Sierras. There are a number on configurations that this filter-tube-bag assembly can be used in and mine was a dirty bag with the filter inline to a drinking tube – worked like a charm. These types of filters do get sluggish and I found that filling a second platty with filtered water and forcing (squeezing) it through the filter in reverse (backwashing) worked well. I would also squeeze the dirty bag to fill my cooking pot quicker – man did I get hungry and couldn’t get some meals done quick enough!

    None of the equipment failed (I’ve put an additional 20 days on it do date) and I would highly recommend this product for the following reasons:

    Ease of use, application flexibility, reliability, durability, and cost.

    Happy trails!

    Mike

    Dec 7, 2016 at 12:31 pm #3439280
    Alice Hengst
    BPL Member

    @moondust

    Locale: Southern Sierras

    I’d like to see a comparison with the new Katadyn gravity filter which I have been using. The Katadyn does not have a “clean bag” but has connections for one. Also, the Katadyn has a great flow rate, which makes filling containers straight from the hose very convenient. I would imagine it might be hard to find a hanging arrangement for both the dirty and clean bag with the Platyplus system where you didn’t need to hold the clean bag while it fills, especially above tree line.  I think the zip bag system of the Platy might be nicer than the folding system of the Katadyn.

    Dec 7, 2016 at 1:10 pm #3439291
    Dan Lee
    BPL Member

    @scoutbuff

    Locale: Colorado

    I have used the 4L version many times with my scout troop and concur with the review as well as comments above.  I have been pondering a 2L version for my personal trips.  Does anyone have experience with replacing the rather large Platy filter with the smaller Sawyer mini?  I’ve read a mixed bag of comments but no real solid evidence that this works well.  (There also appear to be a couple of different Sawyer minis on the market.)  My thoughts would be to leave the dirty bag at home and replace the Platy filter with the smaller/lighter mini.  I’m not a SUL/UL backpacker but always looking to eliminate unnecessary weight.  Appreciate any thoughts…   -dgl

    Dec 7, 2016 at 4:17 pm #3439341
    Josh Belcher
    Spectator

    @jcbelcher

    Locale: Southeastern, U.S.

    I can agree that one use in the field doesn’t constitute a tried-and-true evaluation of a product.  Since then I have used it on a 75 mile AT- Great Smoky Mountains thru-hike and a 27 mile Pinhoti Trail hike (Didn’t hike during the summer months).  I did find in the Smoky’s that the filtering rate decreased and without having the “Clean Bag” in my kit it made it almost impossible to backflush. I have now a 10mL syringe to force flush the filter if it becomes slower and that seems to have helped.  One thing that I’ve found is that I don’t need as much water for individual use as I thought I did. I changed from my 2.5 L bladder and tube setup to carrying two 1 L SmartWater bottles and that makes my water supply last longer. This will likely warrant trying a system like the Sawyer Squeeze or Mini in the future.  However, I do like the convenience of this system as compared to the squeeze type. The dirty water zip-lock fill and the gravity distribution seem much easier than the other systems (as compared to watching my fellow hikers around the water source).  For individual use the weight (approx 4 oz savings) and affordable price may lead me to use a Sawyer Squeeze for individual use and save the Platypus 4.0 L for group adventures or when I take my kids on the trail.  I definitely consider the Platypus a winner for multiple people and for in-camp use filling cook pots, cleaning, and topping off bottles before hitting the trail again.

    Thanks for the comments!

    Dec 7, 2016 at 7:02 pm #3439384
    James Marco
    BPL Member

    @jamesdmarco

    Locale: Finger Lakes

    Good review. On a trip two springs ago (around a year and three quarters) I finished my hike early and hung out at a lean-to for 3 days waiting for my ride. A group of 4 guys came in on week long fishing trip with one of these 4Liter filters (a couple guys came in the next day for a total of 6 in their group.) For the group, it performed really well. Considering the 12oz weight distributed over 6 people, it was about not quite half the weight of my Steripen. They used it extensively over the time I was there (their only clean water supply) and actually used one of the water bladders as a 2nd “dirty” water bag so they didn’t have to go down to the stream so often. I mentioned that they needed to keep the filter from freezing, and they disconnected it each time and put it by the fire as they went out fishing or in one of the sleeping bags at night. (Yup, 30’s-40’s during the day, teens-20’s at night. They had more problems with canisters in the morning than with the water.)

    Anyway, the flow rates were very good over the time that I was with them, just a few minutes that emptied the dirty water into the clean bag. I also mentioned that a higher drop would increase the flow regardless of the position of the filter in a closed system, so they tried it…it worked and may have contributed to the fast flow rates for the three days I was there. One tied to the top of the lean-to and the other at the limit of the tube. Anyway, I usually don’t care for a filter system, way too fiddly for my (usually) solo needs, but was impressed how the system worked for volume their group used.

    Dec 7, 2016 at 8:25 pm #3439405
    Joe Lynch
    BPL Member

    @rushfan

    Locale: Northern California

    My scout troop has used one for trips over the past 5 years for sporadic weekend and 5 day trips over that time mostly in the Sierras. We had one bag holed by a branch when carried outside of a pack but otherwise no issues. Back flushing the filter on trips worked fine for us given that we cleaned the filter after each trip. However, our longest trip was 5 days so your mileage may vary. We used mostly clear water sources with it. Very nice piece of kit. I’m considering getting one for my personal use with smaller bags.

    Dec 9, 2016 at 7:57 am #3439633
    Hank Kaplan
    BPL Member

    @herneseer

    A better back flush for the Sawyer filter is to use a catheter syringe instead of the Leur Lok tip syringe that comes with the Sawyer.  Not familiar with the Platy filter but cutting the catheter tip to fit over the Sawyer output (not inside like the Leur Lok tip) gives a much better fit to really clean out the filter.  The tighter fit locks onto the filter and supports the filter so you can backflush by just holding the syringe, although you may want to support the filter as well.  A “slip tip” syringe may work as well but catheter was what I had and it worked.  From what I could see in the Platy site photos it (or a variation) should work on the Platy filter as well.

    Jan 26, 2017 at 3:03 pm #3447259
    Chris B
    BPL Member

    @bilko

    Nice summary Josh.

    I have also been using one of these with our Scout Troop and for my own personal use and do have a couple of reservations.

    The original filter I had lasted for years with plenty of use and I was very happy with it. The problems started when I had to replace the filter after a trip where the only water source was somewhat green to say the least, I expected to have to replace the filter after this so no problem there. I noticed that the replacement filter was a different design to to original one but thought nothing of it until it blocked on the first trip even though I backwashed after every use. I got home and replaced the filter again and this one also clogged after very little use. The mode of failure appeared to be different with the new filter, the older filter would suffer reduced flow but would always recover after a good backwash, on the other-hand the newer filters seem to totally block and won’t backwash even with a syringe. A bit of a bummer if you don’t have a backup.

    Most of the use has been in the Sierra Nevada with clean water with minimal sediment so I was very surprised to experience clogging with so little use.

    What I did to fix it was replace the filter with element with the one from my Sawyer Squeeze (full size not Mini) and it has worked just fine plus the option to use the syringe to perform a forced backwash is useful.

    This hybrid Sawyer-Pus configuration combines the easy to fill Platypus bags with a reliable Sawyer filter that works for me.

    A common situation that occurs with the Gravityworks that can dramatically reduce flow are air bubbles in the pipe. To fix this problem backwash as soon as you have enough water in the clean bag to do so. Just hold up the clean bag until all the bubbles have bubbled up into the dirty bag and lower it again to resume full flow filtering.

    If you go the Gravityworks as you only filter either take a spare filter element or pack some chlorine dioxide tables.

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